1. Technical Field
The present invention relates to a robot.
2. Related Art
In recent years, automation by industrial robots is ongoing for manufacturing such as automotive body manufacturing. As the industrial robots, industrial robots including robot arms such as a horizontally articulated robot (a SCARA robot) and a vertically articulated robot have been widely used.
In assembly work by such industrial robots, a plurality of robots are set to surround an assembly workbench on a setting surface on which the assembling workbench is set. The plurality of robots perform assembly work for an assembly on the assembly workbench while cooperating with one another.
In the assembly work by the plurality of robots, it is necessary to keep a horizontal state of the robots. As measures for keeping the horizontal state of the robots, the rigidity of a base fixed on the setting surface for the robots is increased. However, the increase in the rigidity of the base causes an increase in costs of the base itself. Further, a rotating range of the robot arms is limited centering on the position of the base.
Therefore, for example, a ceiling hanging SCARA robot hung from a ceiling surface has been developed (see, for example, WO2012/029173 (Patent Literature 1)). Specifically, the ceiling hanging SCARA robot includes a base fixed to the ceiling surface side, a first arm rotatably provided on the base via a first connecting section, a second arm rotatably provided on the first arm via a second connecting section, and a movable shaft section provided in the second arm and movable in the gravity direction.
In such a ceiling hanging SCARA robot, a rotatable range of the first arm and the second arm can be set to 360° or more.
However, in the ceiling hanging SCARA robot in the past, as a stroke amount of the movable shaft section is increased, for example, the connecting section of the first arm and the second arm also increases and vibration tends to occur in the movable shaft section. When the vibration occurs in the movable shaft section, deterioration in working accuracy is caused.